SIGIRR and neoplasm: Since TAMs are known to generally present a pro-tumoral M2-like phenotype [32], we next characterized the phenotype of tumor-infiltrating myeloid cells from MMTV-neu/IL-1R8−/− and MMTV-neu/IL-1R8+/+ tumors of the same size, looking at classic M1 and M2 polarization markers [33].